Edible small bubble foam for suppressing dust in grain handling and storage

ABSTRACT

A method for suppressing dust during grain handling and storage, using small bubble foam created from an edible foam-producing surfactant.

BACKGROUND OF THE INVENTION

The problem of grain-storage explosions has been very serious for manyyears. Grain dust is released from the grain during transport andhandling of the grain. When the dust is confined, as in a grain storageelevator, it can ignite, causing an explosion. Such explosions haveresulted in substantial loss of human life and of property, and, untilnow, no effective solution has been found to the problem.

Howard W. Cole, Jr. has invented a machine and method for making smallbubble foam having bubble diameters from 50 to 200 microns when firstejected from the foam generator as described in U.S. Pat. Nos. 3,811,660and 4,400,220, which are hereby incorporated by reference. A third Colepatent, U.S. Pat. No. 4,207,202, describes an improved version of thefoam generator and is also hereby incorporated by reference. In thosepatents, in order to make suitable foam for dust suppression, air, waterand surfactant are pumped through tortuous passages to form very smallbubbles as explained in those patents. Unfortunately, until now, we havenot been able to apply small bubble foam to grain or other foodproducts, because the surfactants used to make the small bubble foamwere not approved for use with food.

SUMMARY OF THE INVENTION

The present invention solves the problem of accumulating grain dustwhich causes the fires and explosions.

The present invention provides a small bubble foam made entirely ofedible materials for use in conjunction with grains or other ediblematerials.

The present invention provides a method for producing edible smallbubble foam and applying it to grain to prevent explosions in grainstorage facilities.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In an attempt to make an edible small bubble foam for use with grains orother edible materials as described in the patents cited above, wetested many food-based surfactants on Howard W. Cole Jr.'s equipment andfound them to be unsatisfactory. The foams they produced were wet andweak, with insufficient volume formation. They produced foams like thefroth on beer but nothing that would keep its structure for any longperiod of time. We needed a firm foam which would produce small bubblesin the range of 50-200 microns in diameter with an expansion factor of20-40. (The expansion factor is the volume of foam divided by the volumeof water and surfactant used to make the foam.) After extensive testing,we found one edible protein that produced a meringue-type foam with firmholding properties. The bubbles were in the range of 50 to 200 micronsdiameter, and the expansion factor was between 20 and 40. This isexactly what we needed for dust suppression and fire protection ingrains.

The protein we used was a soybean protein purchased from the Guntherprotein division of A. E. Staley Co. and sold under the trademark ofVersaWhip 500. Originally, we purchased the VersaWhip 500 powder, addedhot water to put it into solution, and then used it as the surfactant,combining it with air and water in the machine described in U.S. Pat.No. 4,207,202. Later, we went to the manufacturer of the VersaWhip 500product and bought it in its liquid form, before it was dried to apowder, finding that to be more convenient for our purposes.

We do not know what the VersaWhip 500 is exactly, except that it is apepsin-modified soybean-based protein with sodium benzoate added as apreservative. The manufacturer says that its method of production andcomposition are a trade secret.

Since we are now able to produce the quality of edible foam we requirefor dust suppression, we can apply the foam to the grain at the transferpoints and/or onto the surface of masses of grain as described in U.S.Pat. No. 4,400,220 to suppress the grain dust and thereby protectagainst grain fires and explosions.

What is claimed is:
 1. A method for dust suppression in grain-handlingand storage operations, comprising the following step:a. generating asmall bubble foam by pumping air, water and an edible surfactant throughtortuous passages to produce a small bubble foam having bubble diametersin the range of about 50 to 200 microns and an expansion factor of about20 to 40; and b. applying the small bubble foam to the grain at transferpoints, including the point at which grain falls into the storage bin soas to contact dust particles, causing them to adhere to other particlesso that they fall and do not continue floating in the air; c. whereinthe edible surfactant is a food-based protein.
 2. A method as recited inclaim 1, wherein the edible surfactant is a pepsin-modified,soybean-based protein mixed with sodium benzoate.
 3. A method forsuppressing dust in grain-handling and storage operations, comprisingthe steps of:(a) generating an edible small bubble foam, said bubblefoam having bubble diameters in the range of about 50 to 200 microns andan expansion factor of about 20 to 40, formed by pumping air, water, andan edible surfactant comprised of a food based protein, continuouslythrough a device having tortuous passages; and (b) applying said ediblesmall bubble foam directly to grain in a continuous process at points inthe grain transfer system, wherein said edible small bubble foam isadsorbed by the grain dust particles causing said grain dust particlesto adhere to other particles of grain and grain dust and fall out ofsuspension.
 4. A method as recited in claim 3, wherein the ediblesurfactant is a pepsin-modified, soybean-based protein mixed with sodiumbenzoate.